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Unread 11-01-2006, 23:57
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David Brinza David Brinza is offline
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Re: Calculating Angle to fire at

Quote:
Originally Posted by seanwitte
Theres nothing wrong with that approach, but time is a finite resource and it is not the hardest problem here. It seems to me there are two very difficult problems involved:

1) Build a contraption that consistently shoots the balls at roughly the same speed (and hopefully direction!)

2) Build a gimbal mount that can be quickly and accurately positioned to control the launch angle for the gizmo in part 1.

I think part 2 will be the deal breaker for most teams. Moving an appendage is one thing, but this requires tight tolerances to make it work.
The KISS rule probably applies here (as in most things in life).

You need to understand the relative complexity of items #1 (consistent speed) vs. #2 (agile and accurate gimbal mechanism) and factor in the relative importance of 1 vs. 2. It seems to me that unless you plan to alter the launch angle based on the launch velocity on the current shot, #2 is not very important. If you shoot the ball at fixed angle and consistent speed, you should be able to deliver the ball in the proper height over a rather large range from the goal. I think that's the key in this game.

Hint: play around with the Excel spreadsheet I posted earlier in this thread, now attached below with a minor correction. I now divide by 8 in the drag factor parameter instead of multiplying by 0.128 (obviously I meant to multiply 0.125 in the original version...2% error - my bad!)
Attached Files
File Type: xls AimHigh_traj2.xls (78.0 KB, 100 views)
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Last edited by David Brinza : 12-01-2006 at 00:13. Reason: Attached revised Excel spreadsheet